Battery Charge Question

[jwhposon]

Since the day I installed a second battery I have had constant battery issues. I have one devoted to the starter and one for the stereo and somehow when the batteries get low the engine noise bleeds through. I have a perko battery swtich (1,2,all) and the amps are connected directly from the battery NOT the switch. What I am curious about is, I just replaced both batteries with kirkland, two of them so they are the same battery. I have the positive lines going to the switch and the switch main goes to the starter. What I am curious about is how does the alternator charge the batteries? Does it charge back through the starter somehow?

I have been considering using some sort of relay -- I forget the name but it allows two batteries and will not let one bleed/discharge to the other and when one charges it switches to the other to charge. This would inhibit me from having a backup starter battery but I am all for simplifying as one member mentioned my system is totally screwed up - although it was only because I didn't connect the negative of battery two to battery one. I think there is more wrong and will have an expert look at it this year, for now I just have the embarrassing question of charging?

[sodbuster88]

I would think you definitely need a common ground for both batteries...to the same ground point on the engine. Make sure these grounds are clean. Batterry ground should be common ground with starter and alternator..min to no voltage drops. Might help your noise. Your alternator will charge which ever battery your perko is switched to (in the start charge circuit). If you have connected your batteries properly to the perko, then each will receive charge per the switching.